This invention relates to a novel thermal developing and transferring method in which a developed image is transferred from a photo-sensitive paper to a print paper. In particular, it relates to the transfer of a colored image.
One example of a thermal developing photo-sensitive paper employable in the invention is a color sensitive paper which, as disclosed by Japanese patent application No. 157798/1981 (Japanese patent application Laid-Open No. 58543/1983), contains a pigment carrier which reduces at least photo-sensitive silver halide, organic silver salt oxidizer, hydrophilic binder and pigment expelling agent. As a result of a chemical reaction, the photo-sensitive paper expels a hydrophilic pigment. When the thermal developing color photo-sensitive paper is subjected merely to thermal developing after exposure of the image, a silver image is formed in the exposed portion of the paper while the mobile hydrophilic pigment is provided in the portion thereof which corresponds with the silver image. The photo-sensitive layer is thus composed of negative photo-sensitive material. In other words, the thermal developing color photo-sensitive paper is subjected to image exposure and then to thermal developing, and an oxidation-reduction reaction takes place between the organic silver salt oxidizer and the reduceable pigment carrier with the exposed photo-sensitive silver halide acting as a catalyst. The silver image is formed in the exposed portion of the photo-sensitive paper. In this step, the pigment carrier is oxidized into an oxide by the organic silver salt oxidizer. The oxide is excised under the presence of the pigment expelling agent, as a result of which the mobile hydrophilic pigment is expelled. Accordingly, the silver image and the mobile hydrophilic pigment are provided in the exposed portion, and a color image can be obtained by transferring the hydrophilic pigment onto the print paper.
In the case where the photo-sensitive layer is made of positive photo-sensitive material, the silver image and the mobile hydrophilic pigment are provided in the portion of the material which is not exposed.
The print paper employable in the invention is made up of a support layer and a print layer formed on the support layer. The print layer can receive a pigment which is expelled from the photo-sensitive paper during thermal developing. The print layer contains a pigment agent such as a pigment mordant. Suitable pigment fixing agents can be used selectively according to the properties of the expelled pigment, the other components contained in the thermal developing photo-sensitive paper and the transferring conditions. For instance, a macromolecular weight polymer mordant may be employed as disclosed in Japanese patent application No. 157798/1981 (Japanese patent application Laid-Open No. 58543/1983).